Methods and devices for operating an internal combustion engine using a final controlling element in an exhaust system of the internal combustion engine and using signal production means for producing a signal as a function of a setting of the final controlling element are known in the art.
Thus, engines having turbocharging and including a bypass to the turbine of the exhaust gas turbocharger having a waste-gate valve for controlling the boost pressure are already known. An engine controller controls this waste-gate valve in a suitable manner in order to set a specific boost pressure as a function of the operating point of the engine. Use of an electrical actuator for the waste-gate valve, in which an electrical drive moves the waste-gate valve via a lever mechanism, is known in this case. This electrical drive is provided with a position sensor, such as a potentiometer. The output signal of the position sensor is used in the engine controller for optimal control of the waste-gate valve.
Furthermore, it is known that the recognition of misfires is required for internal combustion engines. Misfires cause a significant increase in the exhaust gas emissions, but they may also cause a high thermal load and therefore damage to a catalytic converter in the exhaust system. Diagnostic methods for recognizing misfires are known in the art.
Published U.K. patent document GB 234 3001, published International patent document WO 99/44028, and published international patent document WO 95/02174 describe the measuring and monitoring of pressure pulsations in the exhaust system via pressure sensors or pressure switches. U.S. Pat. No. 5,824,890, published Japanese patent document JP-2000 205 033, and published Japanese patent document JP-2000 17 05 24 describe the measuring and monitoring of the nonuniformity of the engine speed via a sensor on the crankshaft of the engine. Published European patent document EP 1 039 287, published international patent document WO 90/02874, and published German patent document DE 40 02 208 describe the measuring and monitoring of the exhaust gas composition via suitable sensors, such as HC sensors or lambda probes. U.S. Pat. No. 5,353,636 describes the measuring and monitoring of the torque output via a torque sensor on the crankshaft. Published Japanese patent document JP 08 144 837, U.S. Pat. No. 5,076,908, and published international patent document WO 95/16856 describe the measuring of the cylinder pressure and the monitoring of variables derived therefrom.